1. Field of the Invention
The instant invention relates to top jaws for use on chucks on lathes, milling machines and the like and more particularly to top jaws which can be easily and rapidly interchanged without removing the means by which the top jaw is attached to the chuck.
2. Description of the Related Art
In the art, chucks on milling machines, lathes or the like typically have channels cut into their outer surface. These channels extend radially outward from the center of the chuck. Master jaws are placed in the channels and attached to hydraulic means for moving the master jaws along the channels. These master jaws typically have inverted T-shaped channels extending along their lengths for receiving and securing jaw nuts which are in turn connected to the top jaws.
A jaw nut corresponding in shape to the inverted T-shaped channel of the master jaw is slid along the master jaw to a desired position on the chuck. A top jaw is typically placed on the top surface of the jaw nut above the plane of the outer surface of the chuck. Removable bolts extend downward through the top jaw into threaded recesses in the jaw nut. Upon tightening the bolts, the top jaw is drawn downward into contact with the top surface of the master jaw while the jaw nut is drawn upward into contact with channels in the master jaw. This process locks the top jaw in position on the master jaw.
In order to replace the prior art top jaws, these bolts are removed allowing the top jaw to be pulled away from contact with the upper surface of the jaw nut and master jaw. A new top jaw is positioned above the jaw nut and bolts are passed through the top jaw into contact with the threaded recesses in the jaw nut. The bolts are tightened drawing the top jaw into contact with the upper surface of the master jaw and the jaw nut into contact with the contours of the T-shaped channel.
Aligning and re-threading the bolts through the top jaw into the jaw nut requires considerable manipulation and precise alignment. For this reason, the changing of a top jaw is time consuming and is often very difficult. This is a problem in want of a solution.